Dialysis is a treatment used to support a patient with insufficient renal function. The two principal dialysis methods are hemodialysis and peritoneal dialysis.
During hemodialysis (“HD”), the patient's blood is passed through a dialyzer of a dialysis machine while also passing a dialysis solution or dialysate through the dialyzer. A permeable membrane in the dialyzer separates the blood from the dialysate within the dialyzer and allows diffusion and osmosis exchanges to take place between the dialysate and the blood stream. These exchanges across the membrane result in the removal of waste products, including solutes like urea and creatinine, from the blood. These exchanges also regulate the levels of other substances, such as sodium and water, in the blood. In this way, the dialysis machine acts as an artificial kidney for cleansing the blood.
During peritoneal dialysis (“PD”), a patient's peritoneal cavity is periodically infused with sterile aqueous solution, referred to as PD solution or dialysate. The membranous lining of the patient's peritoneum acts as a natural permeable membrane that allows diffusion and osmosis exchanges to take place between the solution and the blood stream. These exchanges across the patient's peritoneum result in the removal of waste products, including solutes like urea and creatinine, from the blood, and regulate the levels of other substances, such as sodium and water, in the blood.
Many PD machines are designed to automatically infuse, dwell, and drain dialysate to and from the patient's peritoneal cavity. The treatment typically lasts for several hours, often beginning with an initial drain cycle to empty the peritoneal cavity of used or spent dialysate. The sequence then proceeds through the succession of fill, dwell, and drain phases that follow one after the other. Each phase is called a cycle.
Various auxiliary medical devices may be used contemporaneously with dialysis treatments to check the status and progress of the blood or fluid filtration processes. The auxiliary medical devices may include wearable or implantable devices powered by a battery such as a coin cell lithium battery. A coin cell lithium battery has a limited amount of available energy. When such a battery is contained within a human implantable device, the battery is general sealed within the device in order to allow for water ingress protection. Therefore, after a period of time, the battery is drained and the entire device must be replaced. For patients that intend to use the device for many years, the device must be replaced many times. This increases the overall cost of using the device per patient. Furthermore, the size and weight of the device is adversely impacted by the size of the battery. Large size batteries are required for longer periods of operational lifetime. However, increasing the battery size disadvantageously limits patient mobility and the ability to implant the device.